GSTM1 and heart failure: PD patients with high NT-proBNP levels (mean 1141 ± 1530 ng/mL) had a significantly longer duration of PD (p < 0.01) prior to enrolment, a higher prevalence of heart failure (p < 0.01), higher peritoneal Kt/V (p < 0.01) but lower renal Kt/V (p < 0.01), and lower Hb (p < 0.01) levels than those with low NT-proBNP levels (mean 23 ± 14 ng/mL) (Table 1).